Safety switch



R T. KOVAR AND J. F. JIRKA.

SAFETY SWITCH. APPLICATION FILED APR. 11,1921.

Patentedfiaepb. 26, 1922.,

INVENTORS. Frank T, Kovar Joseph EdirKa. 3] g, a

ATTORNEYS.

2 SHEETS-SHEET 1.

Fig.3,

F. T. KovAII AND J. F. JIRKA.

SAFETY SWITCH.

APPLICATION FILED APR. II, 1921.

zl gg gj Patented Sept. 26, 1922 2 SHEETS-SHEET 2.

Fig.4.

IN VEN TORS FrunK T. Kovav Joseph F. J'ITKQ A TTORNEYS Patented Sept. 26, 1922.-

S TE'S PATENT oFFicE.

FRANK '1. KOVAR AND JOSEPH F- JIRKA, OF CLEVELAND, OHIO.

SAFETY sw'rron.

Application filed April 11, 1921.

This invention relates to improvements inv novel safety switches and has general application to a cut-out switch for electric circuits to be controlled in their connection with various devices for heating, lighting or power, or in fact with electric circuits of any description.

The especial form of electric switch which we have devised and shall hereinafter describe has been designed, mainly, for the purpose of preventing or avoiding lingering arcs between the separated portions of the circuit when the latter is intended to be broken, and shall attain this desired result very quickly and positively by the release of a latch that can be operated manually and certainly.

It is a further object of this invention that the release of this safety switch, though applied to brush contacts or to knife blade closing members, shall be practically instantaneous and positive even when the brushes or blades are carried by the movable bar. This desideratum has heretofore been diflicult to obtain.

It is a further object to provide a latch device for a safety electric switch having a movable stem which carries its own latch pin, the means for releasing such pin being situated in a fixed frame.

It is a further object to provide a safety switch control device which will operate in a very quick, positive and efficient manner, which will combine the desired features of simplicity and durability, which will have relatively few parts, and may be manufactured and installed at small cost.

With the above and other objects in view, the invention Consists in the particular features hereinafter more fully described, and more particularly pointed out in the claims.

We will now describe our invention by Serial No. 460,575.

reference to the accompanying drawings, in

-Which- Fig. 1 is a side elevation of a preferred form of a switch embodying our invention showing the circuit closed. '4

F g. 2 is a plan view of the same.

Fig. 3 s a transverse sectional view, the sect on being taken on the line 3-3 of Fig. 1.

Fig. 4 is a side elevation of a modified .form of switch and control; and

Fig. 5 is a transverse sectional view taken on the line 5-5 of Fig. 4.

Referring now to the drawings in detail. thenumeral l0 designates a rectangular base of insulating material, suchas slate, which supports the principal parts of the switch and quick release mechanism therefor. If it is desired to enclose the switch within a wall or junction box, this base may be securedto the bottom of said box. Upon said base 1s secured two supporting posts 2 in longitudinal alinement therewith and near the center thereof; and near the corners of the base or block are secured binding posts 32 to which may be connected outside circult wires or bars which may be led through conduit openings in the ends of the box, if the latter is to be used. Adjacent to the posts are secured contact bars or blocks 5. one pair of binding posts being directly connected to a pair of blocks, the other pair of binding posts being connected indirectly with the corresponding blocks through the intermediacy of fuse contacts 20.

The parts so far described are substantially identical in all views shown, with the exception that clamp contacts 25 in Figs. 4 &- 5 replace the bars 5 used in the form illustrated in the other ,views.

Above the posts 2 is fixed the bearing socket or sleeve 9 which has transverse ears or flanges 11 fastened to the supporting posts Q'by screws 17 If an enclosing box is used, its top plate is fixed between said posts and ears, though it will be readily understood that said plate may be otherwise mounted.

In the form of the device shown in Figs. 1, 2 and-3, the bearing socket or sleeve 9 is hollow to receive a movable verti-plunger, spindle or stem 1 which has a larger portion at the upper end thereof and a reduced.

lower portion 24 projecting without the sleeve 9, and a further reduced portion 28 having a lower screw-threaded end to receive a fastening nut 22. The Wall of the sleeve has integral therewith a lower reduced extension 16 which in turn has an inturned flanged shoulder between which and the shoulder on the stem is positioned a compression spring 3 which maintains the plunger 1 in a normallv raised position, as shown in the dotted line position in Fig. 3.

The spindle or plunger also has a transverse radial socket or cavity 13 in the larger part of the stem which receives and carries an outwardly radially movable latch pin 8 urged normally outward by a spiral compression spring as shown. The socket member also has a transverse and radial socket into which the pin 8 locks when the plunger 1 is in the lowest position. This obviously maintains the switch in closed position. On the fully reduced portion 28 by the nut 22 is secured the transverse bar 6 of insulating material such as fiber composition at the ends of which are secured by bolts 17, brush contact strips, of phosphor-bronze or other good conducting material, whose ends are to bridge the gaps between the bars 5 when the strips are in the down or circuit-closing position of the switch.

To release the stem under the force of the spring 3, the sleeve member 9 has also an enlarged radial opening or cavity 15 in alinement with the reduced socket for receiving the pin 8. In this cavity 15 is a spiral compression spring 4 normally urging the release spindle or shaft 12 outward, but being limited in its action by a fixed pin 30 projecting into a small cavity in the spindle 12. The smaller cavity mentioned is 1n the larger portion of the spindle 12, the latter being provided with a reduced end which just fits and registers with the radial opening in the sleeve 9 in which the pin 8 of the stem 1 locks when the stem is in the down position. To hold the plunger 1 in proper position relative to the fixed parts, preventing rotation, a longitudinal groove 34 may be provided in the plunger 1 in which a key in the sleeve fits. as shown in Figure 2. The same result may also be obtained by providing the groove 19 in the sleeve and the key in the plunger 21 as shown in Figure 4.

In the form shown in Figures 1, 2 and 3, the bar 6 carries brush conducting strips for contact with the bars 5, while in the form shown in Figures 4 and 5 the corresponding insulating bar 26 carried by the spindle 21 has transverse conducting bars inset in its ends to form knife blade contacts for engagement with the clamps 25. The spindle 21 has a single reduced end 31, and the spindle is hollowed out to receive the compression spring 23 which latter is received in a cup or socket 38, resting by external flanges in an opening 39 in the base block. Said cup is of sufiicient internal size to receive the hollow end 31 of the spindle. The parts 31 and 38 therefor telescope easily to provide delicate movement one within the other. The blades 27 are secured in the seats by means of screws 37.

The springs 3, 4 and 23 are quite strong and act very positively. Piano wire is very suitable for the purpose though other material may very likely be used under some conditions.

It will thus be seen that to close the circuit by this switch all that is necessary is to press the plunger down with requisite force and the plunger will be automatically locked in position, and this is true in the use of both forms. In this locked position, the pin 8 has entered the opening in the socket 9. This closed condition of the switch will so remain until the pin 8 has been pushed back into its released position by some outside force, but such force cannot be excrted effectively unless it is directed in aline-ment with said pin. There is therefore little danger of the accidental release of the plunger. It has therefore a very positive element of safety. When, however, it is desired to release the switch, a positive push on the spindle 12 at right angles to the plungers l or 21, will quickly thrust the latch pin 8 wholly within the spindle which at once rises under the very positive force of the springs 3 or 23. This will result in a sudden separation of the switch elements 7 or 27 and the conducting elements 5 or 25. It is found to be a valuable asset of such a control switch that the release shall occur suddenly and positively by the action of a reserve force such as accumulated in either form of the device here disclosedwhen the vertical plunger is thrust downward.

While we have herein shown and described our invention applied to two forms of con ducting elements, and by two forms of bridging or spacing elements. we wish it to be understood that we do not limit or confine ourselves to the precise details of construction herein described and shown, as it is obvious that various features may be modified within the scope of the claims and without departing from the spirit of the invention.

Having now fully described our invention, we claim 1. A safety switch comprising stationary spaced contacts, electrical conducting members for bridging the space between the contacts, a plunger carrying the conducting members. a support for the plunger in fixed relation to the stationary contacts, a spring urging the plunger in a direction to carry the conducting members away from the contacts, relatively movable means carried by the plunger and adapted to engage the support and lock the phmger in position with the conducting members'bridging the contacts, and manually operable means in the support for releasing the locking means, whereby the spring'will open the switch with a snap action.

2. A safety switch. comprising fixed and movable elements, aplunger carrying the in the guide socket for pressing the pin back within the plunger socket.

3. A safety switch comprising stationary contacts and movable circuit closing elements, a longitudinally movable plunger carrying the movable elements and having a radialsocket, a latch pin movable radially in the socket, a spring urging the pin outward, a stationary sleeve surrounding the portion of the plunger having the socket, a radial opening through one side of the sleeve adapted to receive the end of the latch pin and in alignment with the plunger socket when the plunger is in circuit closing position, a release spindle in the 0 ening movable inward to press the pin rom the opening, and means urging the plunger toward circuit opening position.

4. A safet switch comprising stationary contacts an movable circuit closing elements, a plunger carrying the elements and movable longitudinally inward to close the switch and outward to open the switch and having a radialv socket and an enlarged outer end, a coil spring in the inner end of the socket, a latch pin in the socket and entirely receivable therein but urged outward by the spring, a stationary sleeve surrounding the portion of the plunger having the socket, a radial opening through the sleeve in alignment with the socket when the plunger is in switch closing position and having an inner end adapted to receive the outer end of thelatch pin and having a larger outer end, a spindle .in the opening movable inward to press the latch pin from the opening, a coil spring surrounding the spindle in the outer end of the opening and urging the spindle outward, and a coil spring surrounding the plunger and compressed between the enlarged outer end of the plunger and the sleeve.

5.'A safety switch comprising an insulating base, two pairs of separated contact members on the base, a fixed guide member supported above the base having an axial bore and a radial cylindrical opening at right angles to. and communicating with the axial bore, a plunger movable in the axial bore of the guide, an insulating bar on the inner end of the plunger, brush conducting members on the ends of the bar for bridging the contact members on the base when the plunger is in its inner position, spring means within the axial bore for normally urging the plunger outward to move the conducting members away from the contact members, the plunger having a radial socket in position to align with the radial opening in the guide when the plunger is in its inner position, a latch pin in the plunger socket, a compression spring .in the socket back of the pin, the outer end of the pin being adapted to enterthe guide opening when the socket and opening are in alignment, a release spindle movable in the guide opening and having an outer end projecting out of the opening so that pressure exerted thereon will force the spindle inwardly against the outer end of the latch pin and press the our signatures.

FRANK T. KOVAR. JOSEPH F. JIRKA. 

